Rewrite ${((7^{-5})(9^{-5}))^{-7}}$ in the form ${7^n \times 9^m}$.
${ ((7^{-5})(9^{-5}))^{-7} = (7^{(-5)(-7)})(9^{(-5)(-7)})} $ ${\hphantom{ ((7^{-5})(9^{-5}))^{-7}} = 7^{35} \times 9^{35}} $